E-Commerce Course Admin page threw datatable/ajax errors

Tutor
1

I’ve installed the latest Tutor and enabled the discovery/e-commerce plugins. I successfully created a new course in Studio, but I’ve been struggling to specify the price for it.

I followed the instructions on " 6.4.2. Create Course Seats" to create a course but the courses page always pops up an error message about “DataTables warning: table id=courseTable - Ajax error. For more information about this error, please see http://datatables.net/tn/7”. Inspecting the network requests in the browser’s devtools revealed that it was the API call to “/api/v2/courses?format=datatables…” that was returning 502 Bad Gateway error. The same API request without the query parameters would work, and therefore I suspect that it’s the data table configuration that’s causing the error. Any ideas what’s going on? The “Coupons”/“Enterprise Coupons” tabs had the same error (even without any entries created), while “Program Offers”/“Enterprise Program Offers” were fine. Could it be that the Tutor plugin packaged an incompatible UI version?

An additional question is: how exactly should I configure the course price? I have found three possible options but I wonder which one to use:

  1. Create the course in e-commerce course admin for every corresponding course in Studio.
  2. Add a course mode in LMS admin.
  3. Use the Instructor Dashboard per the instructions from section 11.3.1.4 on this page (https://edx.readthedocs.io/projects/open-edx-building-and-running-a-course/en/named-release-cypress/running_course/manage_course_fees.html#configure-the-course). However there is no “E-Commerce” tab that was shown in the screenshot. Perhaps this tab has been removed in the current release?
2

Inspecting the network requests in the browser’s devtools revealed that it was the API call to “/api/v2/courses?format=datatables…” that was returning 502 Bad Gateway error.

502 error means that the service is temporarily unavailable. You did not specify what is the corresponding service: is it ecommerce, discovery, LMS? What is the host name to which the request is sent? What are the logs coming from this service?

3

It was the ecommerce API, and the service was actually available since I could enter this “https://ecommerce.<LMS.ROOT>/api/v2/courses/” in the browser and get a valid response.

In addition, “api/v2/coupons/categories/” and “/api/v2/catalogs/course_catalogs/” worked, but anything that had the query parameters “/?format=datatables&draw=1&…” would fail.

The ecommerce and discovery logs didn’t have any error messages.

Is there any command that I can run to reset all the ecommerce data?

4

I found quite a few entries like this in the ecommerce log:

invalid request block size: 5104 (max 4096)...skip
ecommerce_1         | [uwsgi-http key: ecommerce.<lms_root> client_addr: 172.18.0.15 client_port: 21151] hr_instance_read(): Connection reset by peer [plugins/http/http.c line 647]

Then nginx reported that “upstream prematurely closed connection while reading response header from upstream”.

It seems that I need to increase the buffer size for uwsgi, according to this: https://stackoverflow.com/questions/15878176/uwsgi-invalid-request-block-size. But where can I specify this setting?

5

I tried to added the buffer-size setting to the uwsgi command in Dockerfile like this:

CMD uwsgi \
    --static-map /static=/openedx/staticfiles/ \
    --static-map /media=/openedx/media/ \
    --http 0.0.0.0:8000 \
    --thunder-lock \
    --single-interpreter \
    --enable-threads \
    --processes=${UWSGI_WORKERS:-2} \
    **--buffer-size=${UWSGI_BUFFER_SIZE:8196} \**
    --wsgi-file ${SERVICE_VARIANT}/wsgi.py

but the Dockerfile at “env/build/openedx/Dockerfile” always gets overwritten when running the “tutor config save” command. How do I make this setting persistent, @regis ?

6

Hi @hyx! Thanks for the thorough investigation and detailed report. This is most definitely a bug in tutor-ecommerce. As you discovered, the uwsgi buffer size should be increased. However, to do that, you should not modify the rendered templates from the $(tutor config printroot)/env/ folder, but the actual templates from the tutor-ecommerce plugin: https://github.com/overhangio/tutor-ecommerce/blob/master/tutorecommerce/templates/ecommerce/build/ecommerce/Dockerfile

Would you like to open a pull request on the tutor-ecommerce repo to push your fix upstream? You only need to add a --buffer-size=8192 option to the uwsgi command. There is no need to make this an environment parameter.

If for some reason you do not have the time to open a pull request, please create a Github issue in the tutor-ecommerce repo describe the problem and your proposed solution (and link to this conversation): https://github.com/overhangio/tutor-ecommerce/issues/new

7

Thanks for the prompt response, @regis. I filed an issue for this here: https://github.com/overhangio/tutor-ecommerce/issues/14. Unfortunately I couldn’t submit the PR, since I don’t have the dev setup to test the fix, and also there are three Dockerfiles and I’m not sure which one(s) to fix:
$(tutor config printroot)/env/build/openedx/Dockerfile
$(tutor config printroot)/env/plugins/ecommerce/build/ecommerce/Dockerfile
$(tutor config printroot)/env/plugins/discovery/build/discovery/Dockerfile

1 Like
8

This is resolved in v11.0.1.

9

Nice! But how do I upgrade the ecommerce plugin? I believe I have the new version installed:
$ cat /home/ubuntu/.local/lib/python3.8/site-packages/tutorecommerce/about.py
version = “11.0.1”

However, the list command still shows “ecommerce==11.0.0”:

$ tutor plugins list
discovery==11.0.1
ecommerce==11.0.0
license==11.0.0 (disabled)
minio==11.0.0 (disabled)
notes==11.0.0
xqueue==11.0.1 (disabled)
10

If you have downloaded the tutor binary instead of installing from pip, then tutor will not load your up-to-date plugin.

11

I initially downloaded the binary, but today I ran these commands:

$ git clone https://github.com/overhangio/tutor
$ cd tutor
$ sudo apt install python3 python3-pip libyaml-dev
$ python3 -m pip install -e .
$ python3 -m pip install tutor-ecommerce
12

I uninstalled tutor-openedx and then reinstalled it. Now I get the new version of ecommerce and the 502 error is gone! Thanks for your help, @regis!